OK...you said a couple of code words and had a basic understanding so I didn't know how new you were. A good first step would be to read the 3 steps Matt has written up near the bottom of the home page. Please understand that
MATT IS COMPLETELY WRONG ABOUT MANTIS and they are definately your friend.

(The avatar in my signature are the eyes of a peacock mantis). Regardless of Matt's obvious speciesism against mantis, I forgive him because other than that, he's a real great guy.
OK...let's break this down a little. Bioload equals the amount of animals that you have in a closed system like a tank. If you add too many animals for a particular system, you might accidentally end up with no live animals. There are rules of thumb that a lot of people use but there are other reasons to do exactly what you did. Ask for help. Often there aren't issues with too many animals....some animals just are downright nasty to others and you can accidentally end up with deaths if you don't get the facts ahead of time. For instance, while I've kept mantis in nano tanks with fish for years with no losses, it's not a good idea for most people to attempt it. Other fish are highly territorial and you throw the wrong two fish in a 14g tank together and you might as well have thrown 2 pit-bulls together.
Clean-up crews are shrimp, hermit crabs, snails, etc. that eat uneaten food, fish poo, algae, etc.
Most fish that would be considered a cleaner fish that eats algae, etc. are quite large fish. Even if you bought a baby one, it would quickly get too big for a 14g.